[Amps] Tuned inputs

[Carl]

>
> Henry uses a broadband input for the 8K that seems to function. It is a
> stack of 3 ferrite toroids with Hi bands/Low bands switching. It can be
> purchased as an individual part.
>
> As they say, YMMV!
>
> Carl
> KM1H
>
> ##  It's a basket case excuse for a 'tuned input'
> It consist of 2 un-uns nose to tail.  They step the Z Up.. then turn 
> around,
> and step it back down.  Same deal on all bands except 10m.. where
> they change step down ratio. A relay used to toggle between the
> 2 x output un-un's.    So 3 x un-un's in total.
>
> ## No flywheel action anywhere.  The 8k uses a 3CX-3000A7,.. that has
> a 47-50 ohm cathode Z.    The 8 k manual states NOT to use the auto tuner
> in your xcvr.. and to just ..'put up with the high swr'.   Apparently, 
> things really
> go screwy when the auto tuner used.  With a real tuned input,  input swr 
> is flat,
> and way less drive required.
>
> later... Jim  VE7RF

And what is the operating input VSWR?  I havent heard back about the RF deck 
I worked on yet. Using the tube as a dummy load and with low power it was 
well under 2:1 on all bands.

Carl
KM1H


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